Crude oil column

Shown in Figure 4.2 is a simple refinery flow-sheet. There are many refineries in the world configured in this manner. These are often referred to as simple refineries. In many of these refineries, the crude oil column has greater capacity to the downstream processing units and the refinery sells the excess intermediate streams such as naphtha on the oil market. 

Figure 7.16. Calculation of crude oil column with side strippings using pinch analysis. LN, light naphtha HN, heavy naphtha LD, light diesel HD, heavy diesel.

Hydrogen chloride released dissolves in water during condensation in the crude oil distillation column overhead or in the condenser, which cause corrosion of materials at these locations. The action of hydrochloric acid is favored and accelerated by the presence of hydrogen sulfide which results in the decomposition of sulfur-containing hydrocarbons this forces the refiner to inject a basic material like ammonia at the point where water condenses in the atmospheric distillation column. 

Straight Run Asphalt. In cmde-oil refining, the crude oil at 340—400°C is injected into a fractionating column (5,6,19,20). The lighter fractions are separated as overhead products and the residuum is straight-reduced asphalt. 

The indirect liquefaction basehne design is for a plant of similar size. Unhke the direct hquefaction basehne, the design focuses on producing refined transportation fuels by use of Sheh gasification technology. Table 27-17 shows that the crude oil equivalent price is approximately 216/m ( 34/bbl). Additional technological advances in the production of synthesis gas, the Fischer-Tropsch synthesis, and product refining have the potential to reduce the cost to 171/m ( 27/bbl) (1993 US dollars), as shown in the second column of Table 27-17. 

Atmospheric Distillation - The desalted crude oil is then heated in a heat exchanger and furnace to about 750°F and fed to a vertical, distillation column at atmospheric pressure where most of the feed is vaporized and separated into its... 

Figure 3.4 Two-dimensional separation of dimethylnaphthalenes in crude oil using a 50 m methyl (95%)/phenyl (5%) polysiloxane primary column and a 50 m methyl (50%)/phenyl (25%)/cyanopropyl (25%) polysiloxane secondary column. The top trace indicates the primary separation monitor, while the following chromatograms indicate individual heart-cut secondary analysis. Reproduced from R.G. Schafer and J. Holtkemerr, Anal. Chim. Acta. 1992, 260, 107 (20).

Nevertheless, a number of gas chromatographic applications exist, epecially those for the determination of crude oil indicators. Such indicators are used as geochemical parameters for the thermal history of the crude as well as to indicate the possible relationship between crudes from different wells. These indicators comprise a number of isomeric aromatic species, such as the individual alkylnaphthalenes (44, 45), the individual Cio-mono-aromatics or the individual C9-mono-aromatics. The ratio between these isomers gives a definite indication of the crude oil. In general, these systems use a Deans switching unit to make a heart-cut, which then is focused, reinjected and separated on a second column with a different polarity. 

Production of crude oil and natural gas involves technologies that have become increasingly complex as the remaining resources have become more difficult to locate and remove from their subsurface locations. Many new discoveries are made in sediments below the ocean floor in deep-water, and thus require removal of the oil and gas through long water columns. Other situations now require directional drilling of wells so that production involves transfers along wells that arc far from vertical. 

The atmospheric reduced crude is the feedstock for the vacuum distillation unit. To prevent thermal decomposition (cracking) of the higher boiling point hydrocarbons in the crude oil, the pressure in the vacuum distillation fractionation column is reduced to about one-twentieth of an atmosphere absolute (one atmosphere pressure is 14.7 psia or 760 mm Fig). This effectively reduces the boiling points of the hydrocarbons several hundred degrees Fahrenheit. The components boiling below about 1050°F (565°C) are vaporized and removed as vacuum gas... 

Atmospheric distillation separates the crude oil complex mixture into different fractions with relatively narrow boiling ranges. In general, separation of a mixture into fractions is based primarily on the difference in the boiling points of the components. In atmospheric distillation units, one or more fractionating columns are used. 

In many of the applications of heat transfer in process plants, one or more of the mechanisms of heat transfer may be involved. In the majority of heat exchangers heat passes through a series of different intervening layers before reaching the second fluid (Figure 9.1). These layers may be of different thicknesses and of different thermal conductivities. The problem of transferring heat to crude oil in the primary furnace before it enters the first distillation column may be considered as an example. The heat from the flames passes by radiation and convection to the pipes in the furnace, by conduction through the... 

The open-column technique is commonly applied in the case of crude oils (being the least complex geochemical organic mixtures). MPLC, high-pressure liquid chromatography (HPLC), and PTLC are more often applied to more complex samples, especially those dominated by more polar compounds, such as hydrothermal bitumens or samples showing terrestrial organic matter input, such as extracts or pyroly-sates of coals of various ranks. 

Single-stage flash distillation processes are used to make a coarse separation of the light components in a feed often as a preliminary step before a multicomponent distillation column, as in the distillation of crude oil. 

Surfactants have been widely used to reduce the interfacial tension between oil and soil, thus enhancing the efficiency of rinsing oil from soil. Numerous environmentally safe and relatively inexpensive surfactants are commercially available. Table 18.6 lists some surfactants and their chemical properties.74 The data in Table 18.6 are based on laboratory experimentation therefore, before selection, further field testing on their performance is recommended. The Texas Research Institute75 demonstrated that a mixture of anionic and nonionic surfactants resulted in contaminant recovery of up to 40%. A laboratory study showed that crude oil recovery was increased from less than 1% to 86%, and PCB recovery was increased from less than 1% to 68% when soil columns were flushed with an aqueous surfactant solution.74-76... 

The majority of atmospheric crude oil distillation columns follow the configuration shown in Figure 11.17, which is basically the partially thermally coupled indirect sequence. 

The distillation of crude oil under conditions slightly above atmospheric pressure is limited by the maximum temperature that can be tolerated by the materials being distilled, otherwise there would be decomposition. Further separation of the bottoms of the column (the atmospheric residue) would require higher temperature, and therefore... 

Crude oil distillation is carried out in a complex column sequence in which live steam is injected into the separation to provide the heat required and to reduce the partial pressure of the components to be distilled. The... 

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